From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1ADB81E2606; Tue, 11 Mar 2025 09:56:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741686987; cv=none; b=m3K3YZBip0FJp2+AS+svi0N5GU42dq6QMF/1a5jnheGuJi2BLET+w/QpzCzoIXPkXFRh1PWCAuqNJtCMrZb9PzOcZTfZQvKCI5qbNRNTY4WSa+lPfQ/8Ikm9ez3tIM9iSKsjeb+gdpeOTvKrfNMVOtwRq2Bg4IFErP7nKrlt7qo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741686987; c=relaxed/simple; bh=cGlSSXVSEuK01WXgLlK5ZZp0Gub8yc9YqoK75j3+P/o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HC52bu8WFk+8AzNlL9cQvgyyTwSy9YgYiaOBw7BgIqH5IEmE/NVSSoxzVm9n6RjTwMK20+uzewhncXj75oe7yLNepYA0ylnkbVjkLhXVH5IpCGQyF6e4KfV4wL8Y6JEgQHluABaXFt/6hNqTkeuZtXzD7shKPu/VCTNFEOU/3uY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gsXAyr05; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gsXAyr05" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FB64C4CEED; Tue, 11 Mar 2025 09:56:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741686986; bh=cGlSSXVSEuK01WXgLlK5ZZp0Gub8yc9YqoK75j3+P/o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gsXAyr05H54DpYqK/bZh1TYBhvU9Vwt3WryKG118xyz1w28zF4KIqT8EFm6d+BOjE NHNY4vuQZp69Xi8YKqdBV0dXdYK1ocNLqADDZnYin3lxGeQ1cG9S/Fw03HzV33AW/F OZI3J8MtGU4i9puQyn0/v9fG4azMSY/YaS/UadMKy5hHb8SHWYPcKeMcEeH/R6G+7H mC3I9Z+y3YMjM2czQxPnlWFmkHDJzGfkhf6hdR882nVNaBGd3GHSTETeRwvB5Ik49m UDCQejNw5YHXko61uQQGa3ve1v5AwTB0O3W1ZgEdlR+zvAM7RCwXr/ltdDeS9vM0wH JAkEEJrSO8lcQ== Date: Tue, 11 Mar 2025 11:56:23 +0200 From: Jarkko Sakkinen To: Stefano Garzarella Cc: Peter Huewe , Tom Lendacky , Jason Gunthorpe , x86@kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov , linux-integrity@vger.kernel.org, Dov Murik , Dionna Glaze , linux-coco@lists.linux.dev, James Bottomley , Claudio Carvalho , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Dave Hansen , Joerg Roedel Subject: Re: [PATCH v3 1/4] x86/sev: add SVSM vTPM probe/send_command functions Message-ID: References: <20250311094225.35129-1-sgarzare@redhat.com> <20250311094225.35129-2-sgarzare@redhat.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250311094225.35129-2-sgarzare@redhat.com> On Tue, Mar 11, 2025 at 10:42:22AM +0100, Stefano Garzarella wrote: > Add two new functions to probe and send commands to the SVSM vTPM. > They leverage the two calls defined by the AMD SVSM specification [1] > for the vTPM protocol: SVSM_VTPM_QUERY and SVSM_VTPM_CMD. > > Expose these functions to be used by other modules such as a tpm > driver. > > [1] "Secure VM Service Module for SEV-SNP Guests" > Publication # 58019 Revision: 1.00 > > Co-developed-by: James Bottomley > Signed-off-by: James Bottomley > Co-developed-by: Claudio Carvalho > Signed-off-by: Claudio Carvalho > Signed-off-by: Stefano Garzarella > --- > v3: > - removed link to the spec because those URLs are unstable [Borislav] > - squashed "x86/sev: add SVSM call macros for the vTPM protocol" patch > in this one [Borislav] > - slimmed down snp_svsm_vtpm_probe() [Borislav] > - removed features check and any print related [Tom] > --- > arch/x86/include/asm/sev.h | 7 +++++++ > arch/x86/coco/sev/core.c | 31 +++++++++++++++++++++++++++++++ > 2 files changed, 38 insertions(+) > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index ba7999f66abe..09471d058ce5 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -384,6 +384,10 @@ struct svsm_call { > #define SVSM_ATTEST_SERVICES 0 > #define SVSM_ATTEST_SINGLE_SERVICE 1 > > +#define SVSM_VTPM_CALL(x) ((2ULL << 32) | (x)) > +#define SVSM_VTPM_QUERY 0 > +#define SVSM_VTPM_CMD 1 > + > #ifdef CONFIG_AMD_MEM_ENCRYPT > > extern u8 snp_vmpl; > @@ -481,6 +485,9 @@ void snp_msg_free(struct snp_msg_desc *mdesc); > int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req, > struct snp_guest_request_ioctl *rio); > > +bool snp_svsm_vtpm_probe(void); > +int snp_svsm_vtpm_send_command(u8 *buffer); > + > void __init snp_secure_tsc_prepare(void); > void __init snp_secure_tsc_init(void); > > diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c > index 96c7bc698e6b..2166bdff88b7 100644 > --- a/arch/x86/coco/sev/core.c > +++ b/arch/x86/coco/sev/core.c > @@ -2628,6 +2628,37 @@ static int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_dat > return ret; > } > Since this is an exported symbol, it'd be a good practice document snp_svsm_vtpm_probe(). > +bool snp_svsm_vtpm_probe(void) > +{ > + struct svsm_call call = {}; > + > + /* The vTPM device is available only if a SVSM is present */ > + if (!snp_vmpl) > + return false; > + > + call.caa = svsm_get_caa(); > + call.rax = SVSM_VTPM_CALL(SVSM_VTPM_QUERY); I supposed CAA is some kind of shared memory area for host and VM? > + > + if (svsm_perform_call_protocol(&call)) > + return false; > + > + /* Check platform commands contains TPM_SEND_COMMAND - platform command 8 */ > + return (call.rcx_out & BIT_ULL(8)) == BIT_ULL(8); > +} > +EXPORT_SYMBOL_GPL(snp_svsm_vtpm_probe); > + Ditto. > +int snp_svsm_vtpm_send_command(u8 *buffer) > +{ > + struct svsm_call call = {}; > + > + call.caa = svsm_get_caa(); > + call.rax = SVSM_VTPM_CALL(SVSM_VTPM_CMD); > + call.rcx = __pa(buffer); > + > + return svsm_perform_call_protocol(&call); > +} > +EXPORT_SYMBOL_GPL(snp_svsm_vtpm_send_command); > + > static struct platform_device sev_guest_device = { > .name = "sev-guest", > .id = -1, > -- > 2.48.1 > That said, these are rather self-documenting (i.e, nice and clean). BR, Jarkko